1. Field of the Invention
The present invention relates to a residential facility control system including host and subsidiary apparatus, such as a hot water supply system installed in a housing including a control therefor (host apparatus) and one or more remote controllers (subsidiary apparatus) or an automatic metering terminal system including a terminal network control (host apparatus) for transmitting metering data from one or more metering terminals (subsidiary apparatus), such as a gas meter and water supply meter installed in each housing, to a metering center. The present invention more particularly relates to a residential facility control system having a radio control capability including transmitting and receiving devices for transmitting data between host and subsidiary apparatus.
2. Description of Related Art
A prior art residential facility control system including transmitting and receiving devices includes a remote control device for gas combustion appliances which is disclosed in Japanese Unexamined Utility Model Publication Jikkai-Sho 57-77671. Ignition of the gas combustion appliance is conducted in response to a radio signal from a wireless remote controller. The gas combustion appliance then sends a radio signal representative of ignition of a pilot burner and each burner back to the wireless remote controller. However, a power source for the wireless remote controller is not disclosed and the structure for reducing the power consumption of the wireless remote controller is not disclosed. Therefore, if batteries are used as a power source, a problem will arise that batteries having a high capacity have to be used or frequently exchanged with fresh batteries.
Another prior art residential facility control system including transmitting and receiving apparatus includes a data acquisition system which is disclosed in Japanese Examined Patent Publication Tokko Sho 63-20071. When a calling instruction from a metering center is transmitted via a telephone line to a terminal network control unit (hereinafter abbreviated T-NCU) installed in each house in an automatic metering system using a telephone line, the T-NCU transmits radio waves via radio transmitting and receiving device request metering terminals such as a gas meter, water supply meter, or power meter installed in the house to transmit the metering data. Transmitting and receiving units of the metering terminals then receive the metering data and transmit radio waves representing it to the T-NCU. Use of dry battery cells and solar batteries as a power source for the metering terminal is disclosed. Since no structure for reducing the power consumption of the metering terminals is disclosed, the same problem as that of the above mentioned gas combustion appliances will arise. Use of batteries having a high capacity makes the residential facility control system larger in size and weight and makes its installation more difficult in comparison with compact and light weight similar systems. In order to make the frequent exchange of batteries possible, the residential facility control system has a structure such that batteries are exchangeable. Accordingly, the structure becomes complicated. Since various meters used for metering terminals and hot water supply equipment are usually installed outdoors, the battery exchangeable structure should be resistant to humidity and water. This makes the system structure more complicated.
An automatic metering system is disclosed in Japanese Unexamined Patent Publication No. Tokkai-Hei 4-61432 as a further prior art residential facility control system including transmitting and receiving apparatus. A radio transmitting and receiving device is provided which is coupled with metering terminals and data acquisition devices such as a gas meter, a water supply meter, and a power meter installed in each house via a radio transmission path. Measurement data of a number of metering terminals are collected by the data acquisition devices via the radio transmitting and receiving device on a polling basis. No power source for the metering terminals is described. Since a structure for reducing the power consumption is also not disclosed similarly to the data acquisition system described in the above mentioned Japanese Examined Patent Publication Tokko-Sho 63-20071, the same problem arises.
In a prior art receiver unit for a transceiver in which power consumption is reduced, power is generally periodically supplied to a receiver unit during only a short time slot like the pager disclosed in U.S. Pat. No. 5,150,954. The pager unit which receives a transmission signal including paging and timing data comprises power supply starting means for supplying power to a receiver, a decoder, a first synchronization unit and a display unit for use during only a time slot assigned to the pager unit; the receiver for detecting a transmission signal; the first synchronization unit which responds to a timing data to synchronize with the timing data; and a display unit for displaying the detection of the page. In the pager unit, time information is included in the transmitted signal from a central station. When the pager receives the signal, the pager unit causes a timer to synchronize by using time information included in the signal. This enables the timer which periodically supplies power to the receiver and decoder during a short time slot to be synchronized with the central station. Reduction in power consumption can be achieved since power is periodically supplied to the receiver or decoder during the short time slot for which the timer is set to receive. However, it is essential that the timing data be included in the transmitted signal in the pager. This makes the length of the transmitted signal longer than that of a transmitted signal including no timing data. Correspondingly, the time of signal reception and power supply to the receiver is increased, resulting in high power consumption. Since the pager does not include any transmitter unit, the reduction in power consumption of the transmitter unit of the pager is not disclosed. Synchronization between transmission and reception in such a manner is possible if the transmission and reception is regularly conducted. However, there is the possibility that out-of-synchronization will occur if transmission and reception is irregularly conducted. In other words, if transmission and reception is conducted at time intervals at which out-of-synchronization does not occur, synchronization is achieved by timing data included in the transmitted signal. If transmission and reception is irregularly conducted, transmission and reception may be conducted even though synchronization therebetween is not achieved. Since the receiver can not receive the transmitted signal in such a case, the timing data of the transmitted signal can not be read, resulting in out-of-synchronization. Transmission and reception becomes impossible.